The present invention is intended for use with a fluid-responsive device and a valve for connection with a fluid system. In particular, in its preferred embodiment the present invention comprises a coupling for connecting a pressure switch connection with a valve associated with a compressor in a refrigeration system.
In refrigeration systems, as in many other fluid-type systems, the fluid within the system is toxic or otherwise environmentally harmful. Its escape from the system, especially during connection or disconnection of a pressure switch to a valve within the system, is undesirable. Accordingly, one must ensure that fluid flow-restricting connection of the pressure switch to the valve is effected so that fluid escape from the system is substantially impeded before the valve is actuated to allow fluid communication through the valve.
Further, it is often necessary to damp fluid pressure variations in order that the operation of the pressure switch responsive to fluid pressure is smoothly effected rather than being responsive to every variation of fluid pressure. Such damping has been effected in prior art devices via a number of different approaches. For example, in refrigeration systems where a pressure switch is employed to limit high or low pressure of a refrigerant, and in which high pressure is on the order of perhaps 500 pounds per square inch (psi), unsteady pressure is not infrequently encountered, especially at the high pressure end. To protect the bellows inside the pressure switch (a common pressure-responsive mechanism), there is a need for damping the variations, especially at high pressure. Prior art approaches to providing such damping have included providing a small aperture for access to the bellows; a small aperture with a wire through the aperture to aid in keeping the aperture clean and clear of contaminant build-up; and a capillary tube, which comprises in its most-commonly found embodiment a long copper tube between the pressure switch bellows access and the fluid system access valve. Such a capillary tube allows a larger diameter aperture to be employed (therefore avoiding blockage by contaminants), and generally requires about three feet of tube length in order to assure proper damping is effected.
Another prior art approach to such a damping mechanism is to provide a powdered metal interface between the refrigerant system and the interior bellows or other actuating system of the pressure switch. Such powdered metal interfaces are manufactured under predetermined conditions involving such parameters as particle size, pressure, binder, and the like, to assure that the damper interface is generally capillarized. Thus there is established a network of capillary vias through the damper interface which allow fluid communication through the damper interface while sufficiently damping variations in pressure to protect the pressure switch.
A number of structures have been incorporated in connection with prior art dampers for ensuring automatic actuation of the valve to which the damper is connected as the connection is made. Known structures generally have been specialized structures which significantly add to the cost of making the damper coupler, such as providing cross-members within the coupler to depress the valve stem or otherwise actuate the valve. Another structure provided reduced diameter sections within the coupler connecting a pressure switch with a valve.
It would be useful to provide a simple inexpensive device or structure to accomplish the dual functions of damping fluctuations in fluid pressure to protect interior mechanisms of a pressure switch and timely depressing (actuating) the valve to which the pressure switch is connected by the coupler.
It would also be useful to provide such a device which would actuate the valve automatically during connection to the valve, but where such valve actuation would occur only after sufficient engagement of the coupler with the valve is effected to ensure fluid flow-restricting coupling in order that release of the fluid to the atmosphere may be substantially limited.